The present invention relates to a connection between two longitudinal sections that are at an angle to each other, each section having two connecting sides and two wall sides, where at least one connecting side of each longitudinal section exhibits a groove that is undercut on both sides and an integral longitudinal flange on both sides of the undercut groove, the first longitudinal section being cut transversely and this transversely cut section face forms the end of the first longitudinal section which is secured at an angle to a connecting side of the second longitudinal section. The invention relates further to a process for manufacturing the connection and the use of the connection.
Connections of the above mentioned kind are employed from example in the assembly of frame-type structures for vehicle superstructures e.g. on road and railway vehicles. The structural components are usually made of steel, aluminum or plastic sections, complemented e.g. by shaped steel or aluminum sheets or panels of plastic or if desired plastic or glass segments. Such structural components are in particular made of extruded aluminum, plastic or steel sections.
Connection means for light metal sections utilizing shape and/or friction joining are known. From the Swiss patent CH 627 982 connections based on friction joining of metal sections with the aid of comer connecting pieces are known especially for the assembly of frame-type structures for superstructures of road and railway vehicles. The described comer connecting pieces feature integral spring like parts that are introduced into undercut grooves in the metal sections and secured by screws. The screw connections contain clamping pieces which are introduced into the undercut grooves in the metal sections and then tilted into the undercut parts of the section.
In the connection described in CH 627 982 forces are transferred from one section to the other essentially via the angle piece; often and especially in the case of thin walled sections, this does not provide optimum transfer of forces. Further, in many applications one longitudinal section is often joined to the end of another cross-cut section. In such cases it is necessary to have a clean dividing line at the cut across the latter section. The subsequent working or machining of the cut section end is time consuming and expensive. Further, thin walled sections cannot be well sealed as e.g. filling with a filler material is not possible because there is no proper contact at the joint.
Described in patents DE, A, 38 23 941, GB, A, 919 135 and FR, A, 2 641 809 are nodal joints of pairs of hollow longitudinal sections that are rectangular in cross-section, where the end of one section meets a long face of the other section. Thereby, a square shaped part is inserted into undercuts on the outside of the second section and the end of the first section pushed over the square shaped part so that the square shaped part engages in the end of the first section. The transfer of forces from one section to the other in this known connection is essentially via the outside of the section.
In order to prevent the first section from sliding in the axial direction, the connection according to DE, A, 38 23 941 exhibits deformations in the section wall which engage the square shaped part in recesses. In the case of GB, A, 919 315 and FR, A, 2 641 809 the same effect is achieved by friction, welding or by screwing the first section to the square shaped part.
The present state of the art is such that known connection means are not suitable for joining the end of one longitudinal section e.g. of small cross-section to the long side of another longitudinal section, as the mechanical stability of such a connection is normally inadequate. Further, in the case of known connections, the end of the first longituduinal section lies on the long side of the second longitudinal section so that in such connections, in order to accommodate large forces, the surfaces to be joined have to be of a very high standard.